<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="js/jquery-3.3.1.min.js"></script>
</head>
<body>

<div id="div1">div1...</div>
<div id="div2">div2...</div>
<button id="btn">dianwo </button>
<button id="btn1">dianwo1 </button>
<script>
    /*let $div1 = $("#div1");
    alert($div1);
    let number = 1;
    $div1.html(`<a href="https://www.baidu.com">${number}</a>`);
    let div2 = $("div");
    alert(div2);*/


    $(function (){
        $("#btn").click(function (){
            $("#div1").css("backgroundColor","red");
        })
    });
    $(() => {
       $("#btn1").click(() => {
           $("#div2").css("backgroundColor","#bfa");
       })
    });


</script>
</body>
</html>